[ruby-core:82653] [Ruby trunk Feature#13869] Filter non directories from Dir.glob

Issue #13869 has been reported by naruse (Yui NARUSE).

----------------------------------------
Feature #13869: Filter non directories from Dir.glob
https://bugs.ruby-lang.org/issues/13869

* Author: naruse (Yui NARUSE)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Dir.glob is a tool to fetch filesystem entries with filtering.

On Rails, it often query files from template directories with braces (FNM_EXTGLOB)
https://github.com/rails/rails/blob/6f1c18308ebffc97d51440cdeed7be71de58f26a/actionview/lib/action_view/template/resolver.rb#L247

```
      def find_template_paths(query)
        Dir[query].uniq.reject do |filename|
          File.directory?(filename) ||
            # deals with case-insensitive file systems.
            !File.fnmatch(query, filename, File::FNM_EXTGLOB)
        end
      end
```

By this code, File.directory?() will call lstat(2) system call for each files.

But if Dir.glob is extended, it can avoid calling lstat because it can fetch entry's type from struct dirent
(on many platforms).

```
diff --git a/dir.c b/dir.c
index b7afaec4e0..5db9c2dc79 100644
--- a/dir.c
+++ b/dir.c
@@ -206,6 +206,7 @@ typedef enum {
 #else
 #define FNM_SHORTNAME	0
 #endif
+#define FNM_NONDIR	0x40
 
 #define FNM_NOMATCH	1
 #define FNM_ERROR	2
@@ -1408,7 +1409,7 @@ do_opendir(const int basefd, const char *path, int flags, rb_encoding *enc,
 }
 
 /* Globing pattern */
-enum glob_pattern_type { PLAIN, ALPHA, MAGICAL, RECURSIVE, MATCH_ALL, MATCH_DIR };
+enum glob_pattern_type { PLAIN, ALPHA, MAGICAL, RECURSIVE, MATCH_ALL, MATCH_DIR, MATCH_NONDIR };
 
 /* Return nonzero if S has any special globbing chars in it.  */
 static enum glob_pattern_type
@@ -1581,7 +1582,7 @@ glob_make_pattern(const char *p, const char *e, int flags, rb_encoding *enc)
 	glob_free_pattern(list);
 	return 0;
     }
-    tmp->type = dirsep ? MATCH_DIR : MATCH_ALL;
+    tmp->type = dirsep ? MATCH_DIR : flags & flags & FNM_NONDIR ? MATCH_NONDIR : MATCH_ALL;
     tmp->str = 0;
     *tail = tmp;
     tmp->next = 0;
@@ -1893,7 +1894,7 @@ glob_helper(
     struct stat st;
     int status = 0;
     struct glob_pattern **cur, **new_beg, **new_end;
-    int plain = 0, magical = 0, recursive = 0, match_all = 0, match_dir = 0;
+    int plain = 0, magical = 0, recursive = 0, match_all = 0, match_dir = 0, match_nondir = 0;
     int escape = !(flags & FNM_NOESCAPE);
     size_t pathlen = baselen + namelen;
     const char *base = path;
@@ -1926,6 +1927,9 @@ glob_helper(
 	  case MATCH_DIR:
 	    match_dir = 1;
 	    break;
+	  case MATCH_NONDIR:
+	    match_nondir = 1;
+	    break;
 	  case RECURSIVE:
 	    rb_bug("continuous RECURSIVEs");
 	}
@@ -1940,7 +1944,7 @@ glob_helper(
 		pathtype = path_noent;
 	    }
 	}
-	if (match_dir && (pathtype == path_unknown || pathtype == path_symlink)) {
+	if ((match_dir || match_nondir) && (pathtype == path_unknown || pathtype == path_symlink)) {
 	    if (do_stat(fd, base, &st, flags, enc) == 0) {
 		pathtype = IFTODT(st.st_mode);
 	    }
@@ -1953,6 +1957,11 @@ glob_helper(
 	    status = glob_call_func(funcs->match, subpath, arg, enc);
 	    if (status) return status;
 	}
+	if (match_nondir && pathtype > path_noent && pathtype != path_directory) {
+	    const char *subpath = path + baselen + (baselen && path[baselen] == '/');
+	    status = glob_call_func(funcs->match, subpath, arg, enc);
+	    if (status) return status;
+	}
 	if (match_dir && pathtype == path_directory) {
 	    const char *subpath = path + baselen + (baselen && path[baselen] == '/');
 	    char *tmp = join_path(subpath, namelen, dirsep, "", 0);
@@ -3152,4 +3161,10 @@ Init_Dir(void)
      *  on Microsoft Windows.
      */
     rb_file_const("FNM_SHORTNAME", INT2FIX(FNM_SHORTNAME));
+
+    /*  Document-const: File::Constants::FNM_NONDIR
+     *
+     *  Makes patterns to match non directory.  Valid only
+     */
+    rb_file_const("FNM_NONDIR", INT2FIX(FNM_NONDIR));
 }
```



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